The 3rd Generation Partnership Project (referred to as 3GPP) Evolved Packet System (referred to as EPS) is composed of the Evolved UMTS Terrestrial Radio Access Network (referred to as EUTRAN) and the EPS Evolved Packet Core (referred to as EPC). Wherein, the EPC can support the user access the Global System for Mobile Communication Enhanced Data Rate for GSM Evolution radio access network (referred to as GERAN) and the Universal Terrestrial Radio Access Network (referred to as UTRAN).
The EPC packet core network includes a Mobility Management Entity (referred to as MME), the MME is responsible for the related work of control plane including the management of mobility, the processing of non-access layer signaling, and the management of user safety mode. The MME saves the root key of EUTRAN—Key Access Safety Management Entity (referred to as KASME). In the EUTRAN, the Node-B equipment is an evolved Node-B (referred to as eNB), which is mainly responsible for the wireless communication, the management of wireless communication, and the management of mobility context. The root key of access layer used by the eNB is a Key eNB (referred to as KeNB).
The equipment of the 3GPP Universal Mobile Telecommunication System (referred to as UMTS) system responsible for the management of mobility context, and/or the management of user safety mode is a Serving General Packet Radio Service Support Node (referred to as SGSN). In addition, the SGSN is further responsible for authenticating User Equipment (referred to as UE).
In the 3GPP UMTS system, the equipment responsible for the management of wireless communication is a Radio Network Controller (referred to as RNC) of the UTRAN. FIG. 1 is a flowchart illustrating a security key generating method when a UE handovers from the UTRAN to the EUTRAN in the related art. As shown in FIG. 1, when the UE handovers from the UTRAN to the EUTRAN (i.e. perform the step S101), if the UE and the MME do not save the EPS safety-related parameter such as KASME, the RNC make the MME generate the security key KASME of the EUTRAN by sending a forward relocation request (i.e. perform the steps S102-S104); after the eNB acknowledges a handover request, the MME forwards a redirection replay to the RNC (i.e. proceed to steps S106-S112); the RNC performs a UTRAN handover command (i.e. perform the step S114); the UE side generates the security key KASME of the EUTRAN and handover to the EUTRAN (i.e. perform the step S116).
At present, in the related technology, in the course of handover between different access systems, for example, handover to the EUTRAN from other network, though it is possible to generate the root key KASME of the EUTRAN, it is impossible to generate the security key used by the access layer, for example the root key KeNB of access layer used by the eNB; therefore, the signaling and/or data of access layer can not be protected effectively, and the potential safety hazard exists.